Constant-velocity drive system for gimbaled rotor hubs

Abstract

An aircraft rotor constant-velocity drive system having a differential mechanism that includes a drive disk configured to be integral in rotation with a mast, an upper member at least partially located above the drive disk, a lower member at least partially located below the drive disk, and at least one link connecting the upper member and the lower member to the drive disk such that the drive disk drives the upper member and the lower member in rotation with the drive disk and that the upper member and the lower member are allowed to rotate differently with respect to the drive disk. The link having opposing end joints and a central joint that pivotally engages the drive disk. The system also having a gimbal device configured to drive a rotor hub and to allow gimbaling of the rotor hub with respect to a mast.

What is claimed is: 
     
       1. A rotary-wing aircraft rotor with constant velocity drive, comprising:
 a rotor mast driven in rotation about a longitudinal axis; 
 a hub connected to said mast by a constant velocity drive mechanism and by a tilting arrangement, the constant velocity drive mechanism having:
 a differential mechanism configured to split static torque while allowing relative movement in a plane perpendicular to the longitudinal axis of the mast, the differential mechanism having:
 a first disk; 
 a second disk; 
 a third disk; and 
 a connecting pin having a longitudinal axis parallel to the longitudinal axis of the mast, the connecting pin being configured to hinge to the first disk, the second disk, and the third disk by a three ball joint connection centered about the longitudinal axis of the connecting pin; 
 wherein the first disk, the second disk, and the third disk are placed one above another and are coaxial about the longitudinal axis of the mast; 
 wherein the first disk is positioned between the second disk and the third disk; and 
 wherein the second disk and the third disk are driven by the first disk via the connecting pin; 
 
 
 wherein the tilting arrangement allows pivoting movement of the hub about a flapping axis converging with the axis of the mast and perpendicular to said axis of the mast in such a way that said hub is capable of being driven in constant velocity rotation by said mast about a geometrical axis of rotation of the hub which may be inclined in any direction about the axis of the mast; 
 at least two blades, each linked to said hub by a coupling retaining and hinging the blade in pitch; and 
 two driving devices configured to drive the hub and spaced from the differential mechanism along the axis of the mast. 
 
     
     
       2. A convertible aircraft having at least one tilting rotor movable from a first position in which the or each tilting rotor operates as an airplane propeller to a second position in which the or each tilting rotor operates as a helicopter main lifting rotor, the or each tilting rotor, the convertible aircraft comprising:
 a rotor mast driven in rotation about a longitudinal axis; 
 a hub connected to said mast by a constant velocity drive mechanism and by a tilting arrangement, the constant velocity drive mechanism having:
 a differential mechanism configured to split static torque while allowing relative movement in a plane perpendicular to the longitudinal axis of the mast, the differential mechanism having:
 a first disk; 
 a second disk; 
 a third disk; and 
 a connecting pin having a longitudinal axis parallel to the longitudinal axis of the mast, the connecting pin being configured to hinge to the first disk, the second disk, and the third disk by a three ball joint connection centered about the longitudinal axis of the connecting pin; 
 wherein the first disk, the second disk, and the third disk are placed one above another and are coaxial about the longitudinal axis of the mast; 
 wherein the first disk is positioned between the second disk and the third disk; and 
 wherein the second disk and the third disk are driven by the first disk via the connecting pin; 
 
 
 wherein the tilting arrangement allows pivoting movement of the hub about a flapping axis converging with the axis of the mast and perpendicular to said axis of the mast in such a way that said hub is capable of being driven in constant velocity rotation by said mast about a geometrical axis of rotation of the hub which may be inclined in any direction about the axis of the mast; 
 at least two blades, each linked to said hub by a coupling retaining and hinging the blade in pitch; and 
 two driving devices configured to drive the hub and spaced from the differential mechanism along the axis of the mast. 
 
     
     
       3. A constant-velocity drive system for a rotary-wing aircraft rotor, the constant-velocity drive system comprising:
 a differential mechanism, the differential mechanism comprising:
 a drive disk adapted to be integral in rotation with a mast; 
 an upper member at least partially located above the driven disk; 
 a lower member at least partially located below the driven disk; 
 at least one link connecting the upper member and the lower member to the drive disk such that the drive disk drives the upper member and the lower member in rotation with the drive disk and that the upper member and the lower member are allowed to rotate differently with respect to the drive disk, the at least one link comprising: 
 opposing end joints; and 
 a central joint; 
 wherein the central joint pivotally engages the drive disk; and 
 wherein each of the end joints pivotally engage one of the upper member and the lower member; and 
 
 a gimbal device for driving a rotor hub and for allowing gimbaling of the rotor hub with respect to the mast, the gimbal device being spaced from the differential mechanism along a length of the mast; 
 wherein the upper member and the lower member are adapted to drive the gimbal device in rotation; and 
 wherein each of the opposing end joints and the central joint are ball joints.